McCulloch Chain Saws

[Brian Thacker]

Very nice shop and some very interesting McCullochs.

 

[svk]

Shop is really starting to fill up, added a lathe in the past weeks as well, had to rearrange some things to make room.

Should you have any 70cc Macs that are in your way I'd be interested in taking one off your hands.

 

[Brian Thacker]

Or any PM 800 Cylinders you would want to get rid of.

 

[Brian Thacker]

I am having an issue with my Pro 10-10. If I turn it on it's side it acts like it is flooding. I replaced the crank seals not very long ago. Could it be that they have let go? I cleaned the carb, no help. I replaced the points with a electronic ignition, no help. The only thing I can think of is that the crank seals have let go. Any ideas?

Brian

 

[fossil]

Does it do it when the fuel tank is filled up?

Not sure what you mean by it acts like it's flooding.

 

[Brian Thacker]

It does it with a full tank of fuel. When it is on it's side it misses like it is either running really rich or really lean. Sometimes they can sound the same. I am thinking it is running lean the more I think about it. It just started yesterday and I have not had a lot of time to work with it. I think tomorrow I am going to take the clutch side apart, get it running on it's side and spray some carb cleaner on that seal and see what happens. If that seal is leaking it will change pitch or kill the motor.

 

[heimannm]

Does it act the same warm or cold, or is it more pronounced when it has been running for a bit? Could be that the vent in the fuel cap is not working properly and excess pressure when it is hot causes flooding. Some times the duckbill valves will turn gummy and stop venting either way.

I had a 600 Series saw that misbehaved whenever I tipped the nose down, turned out the mounts were soft and the movement of the saw were actually preventing the throttle from staying fully open.

Mark

 

[Brian Thacker]

Thanks Mark. I have not checked the cap. I will do that first. It seams like it is very cold natured and have to fiddle with it when it's cold to get to run properly. I thought it was the carb stopping up. You know with old equipment that many times you cannot get everything out of the tank. But I took the carb apart and it was very clean. I cleaned it again just in case but no help. This saw I bet had not been used 5 or 6 times in it's life. Very clean. It had been ran dry of fuel before it was stored. It had a bad crank seal when I got it. It had gotten a string wrapped around the seal and burnt it up. So I replaced the crank seals back in May when I got it. I am thinking I might have gotten something else wrapped up in the seal, or maybe the seals I got were just old enough that they were bad when I put them in. I have even thought of the oil pump leaking and when you tip the saw up on it's side the oil runs away from the pump loosing the seal? I don't know. Kind of far fetched but could happen. I really think it's a air leak and I think I am just going to have to break out the can of carb cleaner and go over everything and either find it or eliminate it being a air leak. Just do not understand if it is a air leak that turning it on it's side makes a difference. Maybe the crank shifts a little when tipped?
Thanks Brian

 

[BigBlue]

Is there a chance that fuel is leaking into the carb/airbox area and then causing flooding? Maybe it is coming through the fuel line entry point or a bad seal between fuel tank and airbox.

Rob

 

[Brian Thacker]

The airbox is good and dry. I am having that problem on my Pro Mac 55 and my oldest 10-10 but this saw is dry. Both of these started leaking at the same time. Just my luck. Both are the gasket but not the fuel line. Good thought though.

 

[Brian Thacker]

Well this is what I have found so far. If you turn it up on it's right side (bar side) it will start missing. Does not do it on the left. I sprayed the PTO crank seal with carb cleaner and no change. It won't even idle. I opened up the low adjust about 1/2 turn and it started idling on it's side. I opened the throttle and adjusted the high open about 1/2 turn and it started running fine. I put it back straight and it ran fine or maybe a little rich. I kept going back and forth between straight up and on the right side adjusting for a middle of the road setting. It seams like it is for some reason running lean when it's on it's right side. Not sure what to make of this. I need to let it get cold and try and see if things work right after a cool down cycle and heat back up. I have another carb from a 10-10 Automatic, both a SDC37. I may swap carbs and see what happens.


Brian

 

[ML12]

Does anyone have a cross referenced part number for the seals and bearings on a mcculloch 55? (the 1950's gear drive saw)? I'm planning to rebuild mine. Also, are the seals on all the 80-87cc motors the same?

 

[heimannm]

Seals on most of the 80/87 cc saws are the same, but some early models were different from the later ones. Best I can determine from looking at the IPL's the 44/55 saws had 15 mm bearings (3203) but the seal part numbers (102940) are different from later super series saws.

Best option is take it apart and get the shaft and bore measurements and your bearing supplier can match the seal. Almost all of the seals are standard sizes and can be matched. There were a few odd balls like the extra thin seal on the flywheel side of the super series saws or the large O.D. seals in the gear drives.

Mark

 

[Brian Thacker]

I took the seals out of one of my 10-10s to Applied in Kingsport and they could not match either seal. I know the PTO seal crosses to a modern seal that I saw on there website but did not have the number with me. I did not see the other on there website. So they cannot cross things over very well. Just a FYI. I know the PTO side crosses over to a SK______ number. So it is hard to rely on someone to do their job and cross things over. You may have to just measure them and go on the hunt.

 

[fossil]

SKF 6119 or Timken (National) 253747 is the PTO seal.

Measure the pocket bore and crankshaft dia on the FW side and I'll see if I can cross reference it.

 

[BigBlue]

I have a chance to get a very cheap PM800 that is complete but has a "scored piston". Is it worth my time and effort to buy this and repair it? Is engine repair especially complicated or require special tools? I have taken apart almost all other parts of similar Macs except for the engine and clutch. Are pistons and cylinders available reasonably?

Thanks!
Rob

 

[rwoods]

Pistons are readily available from $50 to $100. Cylinders are scarce. No special tools needed just a little patience. "Very cheap" may mean that the parts alone are worth the price - especially if it has a decent bar. Ron

 

[Brian Thacker]

SKF 6119 or Timken (National) 253747 is the PTO seal.

Measure the pocket bore and crankshaft dia on the FW side and I'll see if I can cross reference it.

I will measure this tomorrow

 

[heimannm]

Applied did not try very hard, those seals are very easy to cross reference.

Mark

 

[Brian Thacker]

They did not seam very helpful. Seamed like they were there for payday and quit time.
I got some seals in from somewhere that were modern seals. I will also look for a part number on those. They looked very good. Looked like stainless construction with a seal at the top inside area of the seal. Very well made. Looked like they would last a long time and seal very well. On the inside edge it had rubber to seal against the bearing.